A turbine stage consists of a rotor and a stator. In a rotor, a circumferential array of aerofoil blades is provided around a circumferential platform of a disc. The disc is mounted for rotation on a rotor shaft. The stator sits adjacent the rotor, upstream of the rotor, and typically comprises a pair of annular platforms in radial and concentric alignment, one platform having a greater diameter than the other. A circumferential array of guide vanes is provided to bridge an annular space between the annular platforms. Adjacent guide vanes form nozzles which serve to accelerate a working fluid towards the rotor.
It is known to join guide vanes to the annular platforms by brazing at junctions within the annular space, the annular space coinciding with an annulus through which the working fluid for the turbine is directed. Such joints are exposed to extreme temperatures and consequently may require shielding or cooling. Where such joints fail, their location within the annulus presents difficulties in accessing and repairing.